The present invention relates to a sliding universal joint to be mounted at a bending portion of a bendable driving axle in an automobile, for example. More particularly the invention is directed to an improvement in a joint including a cylindrical outer member connected to one transmitting shaft and having an inner periphery formed with a plurality of transmitting grooves arranged circumferentially equally spaced from each other and extending axially, an inner member connected to another transmitting shaft and having a plurality of trunnions radially extending to project into the transmitting grooves, an inner roller slidably engaged with an outer periphery of each trunnion, a cylindrical holder having a spherical inner periphery relatively oscillatably engaging with a spherical outer periphery of each inner roller, and an outer roller rotatably supported to an outer periphery of each holder and engaged with the respective transmitting groove.
This type of universal joint is known as disclosed in Japanese Patent Publication No. 57-13211.
In the conventional joint, the spherical inner periphery of the holder is formed with a pair of opposed cutouts. In engaging the spherical outer periphery of the inner roller with the spherical inner periphery of the holder during assembly, the inner roller and the holder are arranged so that an axis of the inner roller is perpendicular to that of the holder. Under such a condition, the pair of opposed cutouts allow the inner roller to be inserted into the holder. That is, the inner roller is inserted into the cutouts, and is then oscillated at an angle of 90.degree. so that the axis of the inner roller coincides with the axis of the holder.
However, as the holder is freely rotatable about its axis, the pair of cutouts are not limited as to the position that they can take during use. Accordingly, when the direction of arrangement of the cutouts becomes coincident with the direction of torque transmission between the outer member and the inner member, effective torque transmitting surfaces of the holder and the inner roller are widely reduced by the cutouts to cause a reduction in durability of the joint.